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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

New trial says, vitamin D prevents progression and deterioration of Parkinson’s Disease

A new randomized controlled trial published in the American Journal of Clinical Nutrition suggests that vitamin D may be able to slow the progression and deterioration of Parkinson’s disease.

Prior research has shown that those with Parkinson’s have lower vitamin D levels than healthy people. Research also shows that for those with Parkinson’s, the lower the vitamin D level, the more severe their disease. In a cohort study that followed people for 29 years, those with the lowest vitamin D levels at baseline had a three times more likely chance of developing Parkinson’s than those with highest levels. And finally, in the United States, those with Parkinson’s that live at more northern latitudes have higher mortality rates than those with Parkinson’s living in southern latitudes, suggesting that lack of vitamin D and/or sun exposure may lead to greater deterioration.

Vitamin D’s active form is expressed in the substantia nigra, the part of the brain that degenerates in Parkinson’s. So researchers here, led by Dr Masahiko Suzuki of Jikei University School of Medicine in Tokyo, Japan, wanted to know, might vitamin D supplementation inhibit the progression of Parkinson’s?

One-hundred twelve patients with Parkinson’s were randomized to either take 1200 IU of vitamin D/day or placebo for 12 months. To assess disease progression, researchers administered standardized scales that score severity of Parkinson’s at both baseline and after 12 months.

Here is what they found:

  • Vitamin D levels in the vitamin D group rose from 22.5 ng/ml to 41.7 ng/ml after one year on 1200 IU/day. The placebo group had similar baseline levels, but their levels did not increase over the year.
  • On the Hoehn and Yahr (HY) scale, a scale to describe symptoms, progress and severity of Parkinson’s, the vitamin D group saw no worsening of natural progression of Parkinson’s, while the placebo group did (p=.0006).
  • The HY score did not worsen over the year in 16 of 55 patients who received vitamin D, while only 7 of 57 patients who received the placebo could say the same (p=.028).
  • In another scale called the UPDRS part II, scores remained unchanged in the vitamin D group, but worsened significantly in the placebo group (p=.004). In contrast, there were no differences between vitamin D and placebo groups in UPDRS total or parts I, III, or IV

The authors concluded,

“In this randomized, double-blind, placebo-controlled trial, daily supplementation with 1200 IU vitamin D3 for 12 months significantly prevented the deterioration of Parkinson’s Disease as measured with the HY stage, UPDRS part II and total, and some domains of the PDQ39.”

To the author’s knowledge, this is the first time a randomized controlled trial has shown benefit in use of vitamin D for patients with Parkinson’s. They caution, however, that at this time it cannot be distinguished whether vitamin D specifically delays progression of Parkinson’s or improves strength and muscle in general, thus making it seem like it helps specifically in Parkinson’s.

More research is needed, however, for the first time ever a clinical trial has demonstrated that vitamin D may be helpful for people with Parkinson’s disease, thus warranting improved vitamin D status through supplementation and sun exposure.


Suziki M et al. Randomized, double-blind, placebo-controlled trial of vitamin D supplement in Parkinson’s disease. Am J Clin Nutr, 2013.

  About: Brant Cebulla

Brant Cebulla was a staff member for the Vitamin D Council from May 2011 to April 2014. He has keen interests in nutrition and exercise.

3 Responses to New trial says, vitamin D prevents progression and deterioration of Parkinson’s Disease

  1. jalfuhaid@juno.com says:

    I’m so glad to see the results of this study. My husband was diagnosed with PD 12 years ago at the age of 48. In 2006, I started giving him 8-10,000 IU of D3 4-5 times a week (daily would have been my preference). After 3 or 4 years, I reduced it to 6000 IU because of his reluctance to take so many vitamins. I have been personally convinced that the D3 has slowed the progression of the disease, and he hasn’t had a single cold since that time! This study backs my hunches and will hopefully make my husband less reluctant to take his vitamins.

  2. Rita and Misty says:


    Glad to see your good results. Please remember that for Vitamin D to be properly utilized by the body, it requires certain co-factors.

    Magnesium and K are of particular importance.

    Since you are a member of the VDC, you most likely already have read this information. But, just in case you haven’t: